1. Field
This application relates generally to wireless communication and more specifically, but not exclusively, to communication scheduling.
2. Introduction
Communication networks enable users to exchange messages among several interacting spatially-separated devices. Communication networks may be classified according to geographic scope, which could be, for example, a wide area, a metropolitan area, a local area, or a personal area. Such networks may be designated respectively as a wide area network (WAN), a metropolitan area network (MAN), a local area network (LAN), or a personal area network (PAN). Communication networks also differ according to the switching technique and/or routing technique employed to interconnect the various network apparatuses and devices. For example, a communication network may use circuit switching, packet switching, or some combination of the two. Communication networks can differ according to the type of physical media employed for transmission. For example, a communication network may support wired communication, wireless communication, or both types of communication. Communication networks can also use different sets of communication protocols. Examples of such communication protocols include the Internet protocol (IP) suite, synchronous optical networking (SONET) protocols, and Ethernet protocols.
In general, wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in radio, microwave, infra-red, optical, or other frequency bands. Consequently, wireless networks are better adapted to facilitate user mobility and rapid field deployment as compared to fixed, wired networks. For example, wireless networks readily support network elements that are mobile and have dynamic connectivity needs. The use of wireless networks also may be preferred for scenarios where it is desirable to provide a network architecture having an ad hoc topology, rather than a fixed topology.
Some types of wireless networks employ one or more access points, whereby each access point provides access to one or more services (e.g., network connectivity) for nearby user devices. These user devices are generally battery powered to enable portability. To conserve battery resources of such user devices, the user devices typically employ a power save mode. For example, a user device will enter a power save mode whenever the user device is inactive. However, to maintain connectivity with any nearby access points, the user device will periodically switch to an active mode (e.g., to determine whether the access point has any information to send to the user device). In contrast, an access point always operates in an active mode to ensure that any user device in the vicinity of the access point will be able to readily communicate with the access point.